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CONCEPTS FOR Anthropogenic Ecotope Mapping (AEM)

Web Version 1.0 (alpha)    February 2006
By: Erle C. Ellis

Overview

This document provides a conceptual basis and overview for Anthropogenic Ecotope Mapping & Classification (AEM; Ellis et. al. 2006).  It is not intended as a stand alone document and is intended solely for use as part of standardized training in the AEM system provided by a qualified instructor.

 

Proper citation of this document:
Ellis, Erle C. 2006.  Concepts for Anthropogenic Ecotope Mapping (AEM) (Version 1.0). Ecotope.org. February 2006.  The Ecotope Mapping Working Group. <Date of Access> <http:/www.ecotope.org/aem/training/concepts/default.aspx>.


Table of Contents

  1. Introduction
  2. Mapping Overview
  3. Mapping Levels
  4. Mapping Strategy
  5. Glossary
  6. References

Long-term ecological changes within densely populated anthropogenic landscapes account for a growing share of global environmental change.  Measuring the causes and consequences of these changes is challenged by their fine spatial scale and complexity (Ellis et. al. 2006)  Anthropogenic ecotope mapping (AEM) was designed to support the measurement of these changes at the fine spatial scales at which they occur, and to integrate these landscape measurements with data on land management practices obtained directly from local land managers and ecological measurements obtained directly by sampled measurements in the field. 

AEM is a standardized ecological mapping procedure designed explicitly for the high-resolution mapping of ecologically-distinct features within densely populated landscapes from a combination of high spatial spatial resolution (≤ 1 m) imagery and intensive fieldwork used to verify the mapping and classification of all features.

Two scale-explicit standards are used in AEM, a Level 1 procedure used for relatively rapid current and historical mapping and an even finer-scale Level 2 procedure used to map sample areas within Level 1 maps, allowing the correction of maps for the finer-scale features left out of Level 1 maps.  

 


II. Mapping Overview

Ecotope mapping is a multi-stage process:

  1. A regional analysis is used to identify Level 1 (L1) sample cells for ecotope mapping.  L1 mapping is the central method for tying together the local, site-specific ecological characteristics of landscapes with the regional characteristics.
  2. Level 1 ecotope features are mapped within the sample AOI's based on interpretation of ≤ 1 m resolution imagery by a combination of direct image interpretation and groundtruthing by experts with local knowledge.
  3. A highly detailed, fine scale, Level 2 (L2) mapping is conducted in sampled small quadrats and/or features within Level 1 mapped areas to observe features and ecological details not measurable using the Level 1 system, such as fine linear features, small structures, riparian zones, field borders, isolated trees, and small patches of managed vegetation. Level 2 data is combined with Level 1 data to estimate areas and amounts of fine-scale patterns.
  4. Regional analysis is completed using Level 1 data supplemented by Level 2 details.

 


III. Mapping Levels 

Level 1: Sample Cell Mapping (L1)
Applied to sample cells selected by a Regional Analysis. Lower resolution direct and ground-truthed interpretation of ≤ 1 m resolution imagery. Classification of both IKONOS imagery & WW2 aerial photos should be possible. L1 mapping is considered the standard mapping system, with Level 2 mapping used to measure fine-scale features within L1 mapped areas.  Mapping is usually accomplished within standardized sample cells (usually 500 m � 500 m square cells), with a single trained interpreter capable of mapping > 1 km2 in < 30 days, including all fieldwork and data processing.  After mapping, sample cells may be reassembled to form maps of different shapes and sizes.
Level 1 Feature Mapping Scales (minimum mapping dimension)
  ≥ 2 m with area ≥ 25 m2 for linear features.
  ≥ 5 m with area ≥ 25 m2 for hard areal features
.
  ≥ 10 m with area ≥ 100 m2 for soft areal features.

 

Level 2: Map Sample Mapping (L2)
Applied to sampled quadrats and/or features within Level 1 mapped sample cells. High-resolution direct and ground-truthed interpretation of features in IKONOS imagery within quadrats sampled within L1 mapped areas or other sample sites. May not be possible for historical aerial photo interpretation at all sites.
Level 2 Feature Mapping Scales (minimum mapping dimension)
  ≥ 0.1 m for linear features.
  ≥ 2 m for hard areal features
.
  ≥ 5 m for soft areal features.

 


IV. Mapping Strategy

Overview. The sequence and scale of feature mapping follows the relative precision by which different types of land use and vegetation features can be identified in 1 m resolution imagery and by groundtruthing using boundaries recognizable to both land managers and to ecologists in the field in the face of land use/land cover confusion.

  1. Map linear features.
  2. Map hard areal (polygon) features.
  3. After mapping linear and hard features, soft features remain in the interstices.
    1. Some small soft features are mapped automatically by being "cut out" of the landscape by enclosure within linear and hard features; these include some features that would otherwise be too small to map as separate soft features.
  4. Map soft areal features with relatively clear edges such as management boundaries, vegetation planting patterns, and recently burned areas.
  5. Map large soft vegetation features without managed or other clear edges within any remaining soft features with area ≥1 ha, whenever contiguous vegetation cover patches ≥ 30 m in dimension (area ≥900 m2) differ significantly from surrounding cover.  This scale rule limits vegetation cover mapping by image interpretation and groundtruthing to larger, more consistently identifiable features and facilitates the use of higher spectral resolution systems (e.g. Landsat) for vegetation classification where vegetation cover varies more gradually.

 


V. Glossary

Linear features have clear edges and length ≥4 times their width, such as roads, paths, ditches, canals, streams, and hedgerows.

Hard areal feature: hard areal (polygon) features have clear edges and relatively homogenous interiors; examples are constructed, barren, and water surfaces and rice paddies.

Soft areal feature: features with fuzzy edges and variable interiors, such as crop plots and patches of trees.

 


VI. References

Ellis E. C., H. Wang, H. Xiao, K. Peng, X. P. Liu, S. C. Li, H. Ouyang, X. Cheng, and L. Z. Yang. 2006. Measuring long-term ecological changes in densely populated landscapes using current and historical high resolution imagery. Remote Sensing of Environment 100(4):457-473. [download]